Method of fabricating piston rings



SPt- 28, 1943 T. A. BOWERS 2,330,549

METHOD OF FABRICATING PISTON RINGS Sept 28, 1943. T. A. BOWERS y METHOD OF FABRICATING PISTON RINGS Filed July 2, 1941 4 Sheets-Sheet 2 Sept. 28, 1943. T. A. BOWERS METHOD OF FABRICATING PISTON RINGS Filed July 2, 1941 4 Sheets-Sheet l 5 Sept. 28, 1943. r. A. BowERs 2,330,549

METHOD OF FABRICATING PISTON RINGS Filed .July 2, 1941 4 sheets-sheet 4 Patented Sept. 218, 19143 UNITED STATES FPAT Erl/.1f@goijfrler: l

12 claims. (cl. .2a-156.6)

This invention relates to piston rings andmore especially to methods of making .piston .rings of sheet materials, and is a continuation in part of my co-pending applications, Ser. No. 276,503, 1

filed May 31, 1939;-Ser. No. 326,340, filed March 28, 1940, now Patent No. 2,311,728, dated February 23, 1943; and Ser. No. 332,219, filed April 29, 1940, noW Patent No. 2,272,632, dated Febru ary l0, 1942.

The chief object of the invention isY to improve piston rings and methods of making piston rings, and to devise methods of fabricating, from piston ring materials, composite structures generally adapted to comprising piston rings, and in particular oil control piston rings. Afurther object of the invention is to present novel methods of making ring portions and ring surfaces and of developing novel resilient characteristics in piston rings. Another object of the invention is to provide a method of making a piston ring from different kinds of piston ring material, with a View to combining resistance to Wear and resilience with the elimination of separate hardening operations. Still another object ofthe invention is to provide a method of making a piston ring made up of a plurality of rows of segments spaced apart by true radial slots or openings. The invention also aims to indicate generally rapid and efficient methods of making piston rings which may be carried out with conventional tool machinery, such as punches, dies, presses and the like. l The nature of the invention, and its objects, will be further understood from the following description of the drawings and discussion relating thereto. I In the accompanying drawings: f Fig. 1 is a plan view fragmentarily illustrating a supporting member'utilized in making a ring in accordance with the method of the invention.

Fig. `2 is a fragmentary perspective view illustrating a strip of piston ring material.

Fig. 3 is a plan View and partial cross section fragmentarily illustrating a step in the method of making a piston ring. f

Fig. 4 is a fragmentary perspective view'of a ring assembly similar to that shown in Fig. 3.

Fig. 5 is a view in end elevation and partial cross section illustrating another stepin the method referred to. Figs. 6 and 7 are cross sectional and perspective views respectively illustratingfurther steps in the method of making a ring.

Fig. 8 is a fragmentary perspective view illustrating still another step in the method.

Fig. 9 is a view in side elevation and partial cross section illustrating a finishing operation.

Fig, 10 is an enlarged fragmentary plan view of a 4finished ring.

Fig. 11 is a plan view of a complete ring. Fig. 12 is a cross sectional view illustrating 'an alternate step infa method of ymaking v'a piston v ring?.

,Fig. 13 is a fragmentary plan'view illustrating another type ofv piston ring material.-

Figs'. 14, 15, andi16 illustrate steps in a modied methodof makingy a pistonring.

Fig. 17 'is a crosssection taken on the line |'l-l'lofFig.16.w.

Figs. 18 and`20 illustratefurther steps in completing a ring .in accordance with the modified method referred to'. Y

Fig. 19 is a fragmentary" perspective `vieW` of pieces of piston ring ymaterial illustrating a, modied type of fastening operation.. v

Figs.`21, 22,123, 24, and 25.illustrate vstill another'modiiicationoi method of making a pist0n ring; and 1 Figs. 26, 2'7 and 28 illustratestill'another modied method of making-piston rings of sheet J Referring to"thefdrawings,-I have illustrated a number of methods of making piston rings, of which Figs.; 1-12 I inclusivel illustrate one general method. Figs'. 13-20 inclusive illustrate anothermethod; and Figs. 2l28` illustrate still ani other method.

l' With referenceftoithe construction included in Figs. 1-12 inclusive, numeral -l vdenotes a supporting member which comprises a rlength'of resilient metal such as steel, Which'is reversely folded to provide bends 2 andl3 and supporting elements 4 which are spaced apartand arranged in parallel relation to one another. A material of suitable strengthis obtained" from a steel Wire, as for example one of .020 of* an inch di'- ameter. 1 i y' l In accordancewith the method 'ofr the invention',1the .supporting member l is attachedbetween strips of piston ring material Sand 6 by.` inserting the bends 2 and3 `in slots -1 formed alonganfedge of eachlof the strips. l The Ispacedapart portions ofthe strips'lforming the sides of the slots l are forcedy toward'one ancthen'while the strips are held in'parallellydispos'ed relationthus tightly pinching Vthe extremities of the bentportionsinthe plane' of each of theA strips, as is illustrated in Figs; 1 3 and 4.

The actual clinchingn operation may be carried out in any. desired manner, as for examplev by passing the ring assembly'shownin Figs. '3 and 4 between upper beveled? rolls as Sand lovverv beveledfrolls as' 9, illustrated` in"-1ig.f5. If desired,

the rolling or pinchingl operation maybe carried out with' sufficientpre'ssure o r force to partially W,v the metal ofthe stripsaround the supportingmember l.

The next stepin the method consists in bending the supporting elements 4 alt-points closely porting elements 4 occur in an upright manner,

with the bends 2 of one side of the supporting member occurring in staggered relation with respect to the bends 3 of theother side of the supporting member.

Thereafter the strips are bent into a circular form to provide a piston ring of some desired size. strips and 6 While supported in spaced-.apart parallel relation by means of the supporting members I I. In this circular spaced-apart posi.- tion, the strips are then partially severed by slots I9 and II, which extend throughout a portion of thewidth of-the strips from the inner periphery of the circular body outward. A `feature of the method of the invention is in the particular disposition of the cuts with respect to the supporting elements 4 and their points of attachment with thestrips 2 and 3.

, Considering first the strip 5, the cutsol extend alongr lines of cutting .which include two of the supporting elements 4 therebetween, as may be observed in Fig. 8. -In the strip 6, however, the cuts II extend along lines of cutting which pass between the two supporting elements 4 included between the rst noted cuts ID of the strip 5. This method of cutting the strips is important in that it later provides for the formation of segments which are circumferentially and radially movable with respect to one an.- other, as will be more fullydescribed hereafter. 'Ih`e arrangement of the supporting elements in the manner noted allows any two of these elements to be attached tol a single severed portion in one of the strips 5, 6, while the same two supporting elements cooperate in connecting severed portions in the other strip.

If desired, the `method of forming thestr'ips into a circular bodY,;aS illustrated in Fig. '7, 'may be carried out .after the slots` I0. and II have been formed in the strips. However, formation of the slots while the strips are in a curved state is preferable for` the reason that radial slotsV formed in the circularly bent body willV be'of the same circumferential width throughout their length, while if these cuts are formed in a straight length of material and the material later bent, the slots will become-substantially wedge-shaped. t p In Fig. 9 I have illustrateda final nishing operation in the method of, making a ring, consisting in removing the outer peripheral portions I2 and I3, of the bent strips 5 and 6. Preferably this may be carried out by the use ofY a rotating grinding wheel I4 against which the ring may be pressed.y The result of this procedure is to completely separate the* strips into segments I5 and I6 of the respective strips 5 and 6, with the segments being spaced apart by interstices orminute openings I 6, which allow forthese segments to be slightly compacted upon one another, as may bemore clearly seen in Figs. and 11 of the drawings.

It will be seen that themethod describedzpr vides a piston ringI body made up of spaced-apart annular rows of segments. The segmentsA within a row are separated; by nterstices I6 andthe ring may be compacted, to` move the. segirrentsV Fig. 7 illustrates the step of bending the movable, the resilient character of the supportinder.

,ing .elements tending to cause the segments to spring apart from a compacted position and thus to develop pressure against the wall of a cyl- In operation in a piston, the ring functions as a gapless ring with its ends adapted to abut one another, and the usual practice is to employ a size of ring which, in its expanded condition, is of a greater circumference than the circumference of the cylinder in which the ring is to be -installed.' By4 so doingthe ring is `helcl in the cylinder in a compactedcondition and tends to exert a radial pressure .outwardly against the cylinder wall. `This pressure allows thering to conform to various irregularities in a cylinder wall surface `and at the same time to exert a uniform pressure all the way around the cylinder wall and throughout all positions in the cycle of movement of the piston in the cylinder.

The method of making' the ring aords several advantages. By using separate pieces of material, it is possible to employ a relatively hard steel for'the strips 5 and 6.0i a character particularly adapted to functioning with the metal of which a cylinder wall may be composed and directed to resisting wear. The supporting elements, on the other hand, may be formed of a tough, resilient steel, chieily designed to develop springiness rather than Aresistance to Wear.

It isl pointed out that in Vobtaining proper toughness and resilience in metal, there may develop resistance to punching, shearing or cutting operations, such as the formation of the slots I0 and other kinds of cuts. By using the differ-4 ent kinds of metal, this dilculty is avoided. The method also affords the .advantage that cuts, such as the cuts I9, may be carried out at various stages in the method of making the ring. For example, the cuts may be `formed ln the strips before their attachment to the supporting member, or they may be formed after attachment but while the supporting member is still in a flat state. Also, the cuts may extend radially al1 the way across the strips so that the segments are. separated without any grinding operations. Still other changes in the method illustrated by Figs. 1-12 inclusive may be resorted to, such as resorting to other means of arranging steel strip material in attached relation to a reversely bent supporting structure. Eig. 12, for instance, illustrates a method of mounting a supporting member Il in a sand mold I8, supported in a container. I9, having openings 20 for allowing molten metal to be poured into the mold I8 to form the strips 2I and 22 which set around the supporting meinber I1.

Figs. 13-20 inclusive illustrate a method of making a piston ring from two strips ofpiston ring material, generally characterized by a process of attaching to spaced-apart strips separate supporting elements, as. compared with a continuous supporting element as illustrated in Figs.- l --12 inclusive.

' For example, strips 2S andA 24 may be provided with openings 425 extending through the strips and having outer enlarged' apertures 2 6. In these openings are secured supporting elements 21 which constitute pins hav'ingreducediend portions 28 adaptedto be engaged through the'openings and be flattened out. in a rivet-like fashion, as illustrated in Fig. 16..y .1 i. y

Any suitable methodof attaching the pinsmay be resorted to', such asthat illustrated in the drawings in .whioha block-:member 29 lis provided with openings adapted to receiveV a plurality ofthe supportingelements 27. `The block 29 also acts as a` spacing member for supporting the strips 23 and :24.while the pins are passed through'. the slots 25 and iiattened over Vin the countersunk openings 26. Y ..1 f Thereafter the stripsfmay be partially severed by openings 32 and 33,-and..bent.around-into .a circular form. Removing the unsevered portions by grinding as above noted providessegments 30, spaced apart bymeans of interstces 3| as illustrated` in Fig. 20. The resilientelements 21 are alternately arrangedbetween the rsegments-to maintain the segments in circumferentially movable relation. I Y

Fig. 19 illustrates a slightly-modifiedtype-of supporting element Sll which consists of afwall member extendingthroughout asubst'antial part of the radial vwidth of strips 35 and 3i, and preferably having projecting ends 31 ,and 3S adapted to engage in openings 33 and il'vof the strips. Supporting elements as Sli are intended to furnish increased stiiiness to the ringby .preventing the top and bottoni sides of the ring Ifrom iiexing towardone another in anaXial direction. VThe advantages already referred to in connection with the'method illustrated in Figs. 1-12 inclusive are also pertinent with respect to .the methods illustrated in Figs. 13-20 inclusive.

Figs. 21-28 inclusive illustrate'another modified method of making a multi-piece piston ring in which a supporting member '2l is secured by' some suitable means, las welding, at thesides of strips 112 and 43,ras particularly illustrated in Fignzfl.,y z

It is intended that a A welding operation may be carried out by'means of a welding wheel which moves continuously overa supporting member as M, disposed on parallelly "arranged strips 42 and i3 'as shown.-' Thesupporting `strip is then bent at right angles in themanner alreadyL described to provide a structure such as that shown in Fig. 25,*and this structure may bel separated into 'segmentsfwhich are Aarranged in annular` s rows to form a piston ring in the Vmanner -already outlined;` i Y 'f If desired, the welding operation may be slightly modified by using separate supporting elements 44 which-are secured tostrips 45 and G6. A piston ring is `obtained by bending the supporting elements lill, cutting' the segments 45, landfarranging the segments in annular rows, as illustrated in Fig. 23. Various other changes and modifications may be resorted to.

While I have shown a preferred embodiment of my invention, it should be understood'that various changes and modifications may be resortedto, in keeping with the spirit of the invention as defined by the appended claims.

' I claim:

l. That improvement inmethods ormaking.

piston rings which comprises attaching to spacedapart parallelly arranged strips of piston ring material a plurality of supporting portions of a second piston ring material, then cutting one ofthe strips along lines of cutting which extend transversely of the strips to form a plurality of separated segments, each of which includes two ofthe said supporting elements' attached thereto, and I cuttingr the' other of thef strips along lines of cutting which extend transversely between the said rst lines of'cutting. i

2. yThat improvement in methods of making a piston ring which comprises securing between they y v cutting a second strip alongtransverse lines' of cutting to form segments whichinclude two adjacent supporting elements which'arefattached to separate segments of the said rst. strip bending the strips into'a circular shape. i 3. That improvement in methods of making piston rings which comprises securing between two vspaced-apart par'allelly arranged' strips of piston ring 'material a vpluralityof supporting portions of afsecond piston ring material, then cuttingfone of the strips along vtransverse lines of cutting which include two of the supporting elements, cutting the seco-nd strip along transverse lines of cutting which pass between any two of the supporting elements included between the said rst lines of cutting said lines of cutting extending from one edge or" each of :the respective strips to* a point within an opposite edge of each of zthe said strips bendingthe strip into-a circular shape and grindingft'he circularly bent strips torremove outer peripheral portionsand extend the lines of'y cuttingthroughout the radial width of the'strips, Y 1 l v.

V4. That improvement -in methods'of making Piston rings which comprises securing between two spaced-apart parallelly arranged' strips of pisa" ton ring material ya plurality of supporting portions of aV second piston,ringmateriah`1 partially cutting one .of the strips along ,transversel lines of cutting which include two of the supporting-- elements, partially cutting the'second Istrip along transverse lines of cutting which passlbetween any two of'thesupporting` elements included between the said first lines of cutting, bending the strips into a circular shape, and then removing portions from each of the outer peripheries of the circularly-bent strips to form rows of separated segments;

'5;That improvement in methods of making piston rings which comprises securing between two spaced-apart parallelly arranged strips` of piston ring material a plurality of supportinglr portions of another piston ring material, then bending'the supporting portions to arrange the strips in a substantially parallel spaced-apart re'- lationship at right angles to the supporting ele-KV ments, bending the strips into a circular form; then cutting one of the strips along transverse lines of cutting which include two of the supporting elements, and cutting the second strip along transverse lines of cutting which p'ass between any two of the supporting elements included'between the said first lines of cutting.

6."Ihat improvement in methods oi' making piston rings which comprises securing between twol spaced-apart parallelly arranged strips of piston ring material a plurality of separated supporting portions of another piston ring material.

- thenr bending the supporting portions to arrange 

